Ideal Weight Calculator
Devine and Robinson ideal-weight references from height and sex.
This ideal weight calculator estimates a reference "ideal body weight" range using two long-standing medical formulas — Devine and Robinson — that were originally developed for calculating safe drug dosages, not for defining beauty or fitness standards. Enter your height and sex, and the tool returns a comparison range rather than a single rigid number.
"Ideal weight" is a historical clinical term, not a personal judgment. These formulas ignore muscle mass, bone density, frame size, and ethnicity, so treat the output as one reference point among several — alongside BMI, body fat percentage, and how you actually feel and perform.
On this page
The Devine Formula
Developed by Dr. B.J. Devine in 1974 originally to help dose medications based on body weight, this formula remains one of the most widely cited "ideal body weight" equations in clinical settings today.
Men: Ideal weight (kg) = 50 + 2.3 × (height in inches − 60). Women: Ideal weight (kg) = 45.5 + 2.3 × (height in inches − 60). Both formulas assume a baseline height of 5 feet (60 inches) and add 2.3 kg for every inch above that.
The Robinson Formula
Published in 1983 as a refinement of earlier work by Dr. J.D. Robinson, this formula uses a slightly different baseline weight and per-inch increment, generally producing a marginally lower estimate than Devine.
Men: Ideal weight (kg) = 52 + 1.9 × (height in inches − 60). Women: Ideal weight (kg) = 49 + 1.7 × (height in inches − 60). Comparing both formulas side by side gives you a realistic range rather than one falsely precise number.
A Worked Example
Consider a woman who is 165 cm tall (about 65 inches). Using Devine: 45.5 + 2.3 × (65 − 60) = 45.5 + 11.5 = 57 kg. Using Robinson: 49 + 1.7 × (65 − 60) = 49 + 8.5 = 57.5 kg.
Both formulas land close together here, around 57–57.5 kg, giving her a reasonable reference band rather than a single fixed target to chase.
Why These Formulas Have Real Limits
Devine and Robinson were built from limited historical datasets and do not adjust for frame size, muscle mass, or ethnic variation in healthy body composition. A muscular athlete will typically weigh well above these figures while still being lean and healthy, and older adults with reduced muscle mass may sit within range while carrying more fat than is ideal.
For a fuller picture, pair this reference range with your BMI Calculator result and, if useful, a Body Fat Calculator estimate. Sustainable habits — consistent strength training, adequate protein, good sleep, and regular movement — matter far more for long-term health than hitting any single number on a chart.
Other Historical Ideal-Weight Formulas
Devine and Robinson are the two most commonly cited formulas today, but several older references exist, including the Hamwi formula (popular with dietitians since the 1960s, using slightly different per-inch increments) and the simple Broca index, which subtracts 100 from height in centimetres for men and 105 for women as a rough historical rule of thumb.
These older formulas generally agree with Devine and Robinson within a few kilograms for average heights but can diverge more noticeably at the extremes of height, which is another reason to treat any single "ideal weight" figure as a loose reference band rather than a precise target.
Medical Disclaimer
This tool is for general screening and education only. It is not a medical device and does not replace advice from a doctor, dietitian, or other qualified health professional — especially if you are pregnant, under 18, managing a chronic condition, or taking medication that affects weight or metabolism.